Quinqueloculina neostriatula Thalmann 1950

Mamo, Briony L., 2016, Benthic Foraminifera from the Capricorn Group, Great Barrier Reef, Australia, Zootaxa 4215 (1), pp. 1-123 : 38-39

Quinqueloculina neostriatula Thalmann 1950 ( Fig. 8 :10–21)

1932 Quinqueloculina striatula Cushman , p. 27, pl. 7, figs 3, 4.

1950 Quinqueloculina neostriatula Thalmann , p. 45.

1992b Quinqueloculina neostriatula Thalmann ; Hatta & Ujiié, p. 68, pl. 8, fig. 2a, b. 1997 Quinqueloculina neostriatula Thalmann ; Haig, p. 272, fig. 4:1. 2008 Quinqueloculina neostriatula Thalmann ; Strotz, p. 140, fig. 4k. 2012 Quinqueloculina neostriatula Thalmann ; Debenay, p. 124, pl. 7.

Description. See Cushman (1932, p. 27, pl. 7, figs 3, 4) and Debenay (2012, p. 124, pl. 7).

Remarks. Specimens assigned to Quinqueloculina neostriatula Thalmann 1950 have a quinqueloculine chamber arrangement, an oval test outline that is slightly longer than broad, distinct sutures that are slightly depressed, walls with carinate ornament and numerous, fine, incised, slightly oblique lines that vary in depth from shallow to significant grooves ( Fig. 8 :10–21). It is distinguished from other Quinqueloculina species by its finely to deeply incised carinate ornament and broad aperture with a lip and large tooth. It differs from other carinate ornament bearing quinqueloculine species in the size and shape of the apertural dentition and the intensity and fineness of costae.

This species, originally erected by Cushman (1932) as Quinqueloculina striatula Cushman 1932 , was later reassigned to Quinqueloculina neostriatula by Thalmann (1950). Cushman’s (1932) original description of Q. striatula stated that this species had subacute peripheries giving it a triangular cross section, but the specimens published by Debenay (2012) vary between angular and well-rounded peripheries whilst those collected from the CG and published by Hatta & Ujiié (1992b) and Strotz (2008), all have well-rounded peripheral margins. In addition to this, Cushman (1932, pl. 7, figs 3, 4) described the dentition as a large, flat tooth that nearly filled the entire aperture, yet provided illustrations showing no dentition at all. Similarly found by Debenay (2012), specimens collected from the CG show variable morphology including the depth and thickness of costae and width of dentition. Juvenile specimens ( Fig. 8 :10–13) tend towards a more restricted aperture and a narrow base to the bifurcate tooth. Adult specimens that have been broken ( Fig. 8 :14, 15) show earlier chambers possess these features while the outermost chambers of unbroken specimens ( Fig. 8 :16–21) display a broadened aperture and, like specimens published by Hatta & Ujiié (1992b), Haig (1997) and Debenay (2012), have a large, strongly contorted, often flattened, slightly bifid tooth ( Fig. 8 :12, 14).

This species has a mostly western Pacific distribution ( Fiji Islands—Cushman 1932 and Strotz 2008; Ryukyu Island Arc—Hatta & Ujiié 1992b; Exmouth Gulf—Haig 1997; New Caledonia southwestern lagoon down to 35 m—Debenay 2012).

Distribution within study area. Quinqueloculina neostriatula accounted for over 3% of all foraminifera collected from the CG and is the second most abundant taxon collected after Q. bosciana from the CG with an average number of 17 specimens per site. Greatest abundance was found at sites 40 and 42 from Heron Lagoon and site 18 in One Tree Lagoon 3. Specimen numbers were distinctly low with only 1– 2 specimens per site along Transect 2 on Heron Reef between the inner and outer reef flats. Sykes Reef was the only location where this species was not found.

Figures

FIGURE 8. (Unless otherwise specified all scale bars = 100 µm). 1 – 2. Quinqueloculina cf. Q. agglutinans d’Orbigny, 1839. QM # G 465786 from ST / HW 2, lateral view (1), scale bar = 200 µm and oral view (2), scale bar = 200 µm. 3 – 4. Quinqueloculina baccaerti n. sp. QM # G 465818 from OTI 36. 3. Lateral view. 4. Oral view. 5 – 7. Quinqueloculina bosciana d’Orbigny, 1839. QM # G 465978 from WL 21, lateral view (5), oral view (6). 7. QM # G 466135 from OTI 36, lateral view. Scale bar = 50 µm. 8 – 9. Quinqueloculina latidentella Loeblich & Tappan, 1994, QM # G 465825 from OTI 36. 8. Lateral view. 9. Peripheral view. 10 – 21. Quinqueloculina neostriatula Thalmann, 1950. 10 – 11. QM # G 466102 from WL 19, lateral (10) and oral (11) views. 12 – 13. QM # G 465984 from OTI 52, lateral (12) and oral (13) views. Scale bar for 13 = 50 µm. 14. QM # G 466071 from HL 40, oral view. 15. QM # G 466068 from HL 40, close-up oral view. Scale bar = 50 µm. 16 – 17. QM # G 465983 from WL 21, lateral (16) and oral (17) views. Scale bar for 16 = 200 µm. 18 – 19. QM # G 465833 from OTI 39, lateral (18) and oral (19) views. Scale bar for 18 = 200 µm. 20 – 21. QM # G 466096 from OTI 52, lateral (20) and oral (21) views.